This undated photo provided by Nasa shows Saturn's moon Enceladus. The 'tiger stripes' are long fractures from which water vapor jets are emitted.

Washington - A vast ocean of water could be lurking under the thick ice of one of Saturn's moons, according to findings published by Science magazine on Thursday.

A sea up to 10 kilometres deep lies beneath 40 kilometres of ice at the south pole of Enceladus, extending over most of its southern hemisphere, an analysis by Nasa's Cassini probe showed.

Water is considered one of the essential criteria for a planet or moon to support life. It has also been found in our solar system on Titan, also orbiting Saturn, and Europa, one of Jupiter's moons.

Cassini has been exploring Saturn and its satellites since 2004. The spacecraft measured the gravity and movement of Enceladus during three flybys to calculate its internal structure.

It found that the ocean probably sits on a bed of silicate rock. This could leach phosphorous, sulfur, potassium and sodium into the water, essential elements for the formation of life as we know it, study co-author Jonathan Lunine of Cornell University said. - Sapa-dpa